Nuclear Theory·nucl-th

Monday·January 3, 2022

12 papers—3 primary·9 cross-listed

01
[Submitted on 30 Dec 2021]
Superfluid density in disordered pasta phases in neutron star crusts
Zhao-Wen Zhang · C. J. Pethick
We calculate the superfluid density of nucleons in disordered pasta phases in the inner crust of neutron stars using an effective medium approach which parallels that previously used for calculating the electrical conductivity of terrestrial matter. We allow for the effect of entrainment, the fact that the current density of one species of nucleon depends on the gradient of the phase not only of the same species but also of the other species. The superfluid density tensors for the perfectly ordered pasta phases are very anisotropic, and we derive expression for the effective superfluid densities of the disordered phases.
Comments:
7 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.15160 [pdf]
PRC(2022)·3 citations
02
[Submitted on 31 Dec 2021]
Nuclear states projected from a pair condensate
Yi Lu · Yang Lei · Calvin W. Johnson · Jia Jie Shen
Atomic nuclei exhibit deformation, pairing correlations, and rotational symmetries. To meet these competing demands in a computationally tractable formalism, we revisit the use of general pair condensates with good particle number as a trial wave function for even-even nuclei. After minimizing the energy of the condensate, we project out states with good angular momentum with a fast projection technique, allowing for general triaxial deformations. To show applicability, we present example calculations from pair condensates in several model spaces, and compare against projected Hartree-Fock and full configuration-interaction shell model calculations. This approach successfully generates spherical, vibrational and rotational spectra, demonstrating potential for modeling medium- to heavy-mass nuclei.
Comments:
8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2112.15393 [pdf]
PRC(2022)·13 citations
03
[Submitted on 31 Dec 2021]
Entanglement and seniority
J. Kovács · A. T. Kruppa · P. Salamon · Ö. Legeza · G. Zaránd
We study mode-entanglement in the seniority model, derive analytic formulas for the one-body reduced density matrix of states with seniority $ν = 0, 1, 2$ , and $ν = 3$ , and also determine the particle number dependence of the one-body reduced density matrix for arbitrary seniority. We carry out numerical calculations for the lightest calcium isotopes and for $^{94} Ru$ nucleus, and investigate the structure of their ground and low energy yrast states. We investigate the fulfillment of several predictions of the seniority model regarding the behavior of one-mode entropies, which we compare with the results of configuration interaction (CI) and density matrix renormalization group (DMRG) computations. For $^{94} Ru$ , the seniority model accounts for the $0 g_{9/2}$ mode entropies, but seniority mixing is important for certain yrast states. Interaction induced quantum fluctuations decrease the occupation of the $0 f_{5/2}$ , $1 p_{3/2}$ and $1 p_{1/2}$ shells, and amount in finite mode entropies on these shells, too, clearly outside the scope of the simple $(0 g_{9/2})^{4}$ seniority model. The $0 f_{7/2}$ shell based seniority model is more accurate for the light $Ca$ isotopes, but seniority mixing is substantial for some $^{44} Ca$ yrast states, too.
Comments:
13 pages, 7 figures
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); physics.chem-ph (physics.chem-ph)
arXiv:
2112.15513 [pdf]
PRC(2022)·43 citations
04
[Submitted on 25 Dec 2021] (cross-list from hep-ph)
Heavy flavor molecular states with strangeness
Kan Chen🇨🇳 · Bo Wang🇨🇳 · Shi-Lin Zhu🇨🇳
We proposed a unified framework to describe the interactions of the observed $T_{cc}$ , $P_{c}$ , and $P_{cs}$ within a quark level interaction in our previous work. In this work, we generalize our framework to the loosely bound hadronic molecules composed of heavy flavor di-hadrons with strangeness. We predict the possible $D^{(*)} D_{s}^{(*)}$ molecular states in the SU(3) limit with the masses of the $P_{c}$ states as the inputs. We also investigate the baryon-meson and baryon-baryon systems and consider the SU(3) breaking effect in their flavor wave functions. We generalize our isospin criterion of the formation of heavy flavor di-hadron molecules to the $U / V$ spin case. For a specific heavy flavor meson-meson, baryon-meson, or baryon-baryon system, the interactions for the states with the same flavor and spin matrix elements can be related by a generalized flavor-spin symmetry.
Comments:
11 pages, 13 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.13203 [pdf]
PRD(2022)·28 citations
05
[Submitted on 29 Dec 2021] (cross-list from astro-ph.HE)
Neutron diffusion in magnetars as a source of astrophysical bursts
C.A. Bertulani · R.V. Lobato
Neutron tunneling in neutron star crusts can release enormous amounts of energy on a short timescale. We have clarified aspects of this process occurring in the outer crust regions of neutron stars when oscillations or cataclysmic events changes the crustal ambient density. We report a time-dependent Hartree-Fock-Bogoliubov model to determine the rate of neutron diffusion and conclude that a large amount of energy, in the range of 10^40 - 10^44 erg, can be released rapidly. We suggest that this mechanism may be the source of hitherto unknown phenomena such as the Fast Radio Bursts (FRBS).
Comments:
10 pages, 4 figures, contribution to the XLIV Brazilian Workshop on Nuclear Physics to be published by the IOP
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2112.14817 [pdf]
J.Phys.Conf.Ser.(2022)·0 citations
06
[Submitted on 30 Dec 2021] (cross-list from hep-lat)
Lattice QCD calculation of the two-photon exchange contribution to the muonic-hydrogen Lamb shift
Yang Fu🇨🇳
We develop a method for lattice QCD calculation of the two-photon exchange (TPE) contribution to the muonic-hydrogen Lamb shift. To demonstrate the feasibility of this method, we also present an exploratory study with a gauge ensemble at $m_{π} = 142$ MeV. By adopting the infinite-volume reconstruction (IVR) method along with an optimized subtraction scheme, we obtain a preliminary result of the TPE contribution which agrees well with previous calculation using other methods and one magnitude smaller compare to the large $\sim 300 μ$ eV discrepancy for the proton radius puzzle.
Comments:
11 pages, 4 figures, Proceedings of the 38th International Symposium on Lattice Field Theory, 26th-30th July 2021, Zoom/Gather@Massachusetts Institute of Technology
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.14913 [pdf]
PoS(2022)·2 citations
07
[Submitted on 30 Dec 2021] (cross-list from hep-ph)
Perturbative and non-perturbative interactions between heavy quarks and quark-gluon plasma within a unified approach
Wen-Jing Xing🇨🇳 · Guang-You Qin🇨🇳 · Shanshan Cao🇨🇳
While perturbative QCD is sufficient for understanding the color, mass and energy dependences of parton energy loss and jet quenching at large transverse momentum in heavy-ion collisions, a simultaneous description of heavy flavor nuclear modification factor $R_{AA}$ and elliptic flow coefficient $v_{2}$ at low and intermediate $p_{T}$ still remains a challenge due to the effects from non-perturbative interactions. In this work, we extend the linear Boltzmann transport model by implementing a generalized Cornell-type potential that incorporates both short-range Yukawa interaction and long-range color confining interaction between heavy quarks and the QGP medium. Combining our new approach for heavy-quark-QGP interaction with a (3+1)-dimensional hydrodynamic model CLVisc for the QGP evolution and a hybrid fragmentation-coalescence model for heavy quark hadronization, we obtain a satisfactory description of heavy meson $R_{AA}$ and $v_{2}$ from low to intermediate to high $p_{T}$ observed at both RHIC and the LHC. By model-data-comparison, we extract for the first time the in-medium heavy quark potential from open heavy flavor measurements; the result is in agreement with the lattice QCD calculation. Our study indicates that while jet quenching at high $p_{T}$ is dominated by perturbative QCD interactions, non-perturbative interactions are indispensible for understanding heavy flavor quenching and flow at low and intermediate $p_{T}$ .
Comments:
9 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2112.15062 [pdf]
PLB(2023)·35 citations
08
[Submitted on 30 Dec 2021] (cross-list from physics.atom-ph)
Collision-induced radiative quenching and other disintegration modes of the $2 S$ state of muonic hydrogen and deuterium atoms
V.P. Popov🇷🇺 · V.N. Pomerantsev🇷🇺
The formation and various disintegration modes of $2 s$ states for muonic hydrogen and deuterium atoms at kinetic energies both above and below the $2 s - 2 p$ threshold are studied. The cross sections of the collision-induced radiative quenching, elastic scattering, and Coulomb deexcitation of $(μ^{-} p)_{2 s}$ and $(μ^{-} d)_{2 s}$ atoms in collisions with ordinary hydrogen and deuterium atoms at collision energies below the $2 s - 2 p$ threshold are calculated in the framework of the close-coupling approach. The basis set includes all open and closed channels corresponding to exotic-atom states with principal quantum number $n$ from 1 up to 30. Results of these numerical quantum-mechanical calculations of cross sections are used as input data for detailed cascade calculations. The kinetics of atomic cascade for $μ^{-} p$ and $μ^{-} d$ atoms is studied in the wide range of the relative target densities, $φ = 1 0^{- 8} - 1$ applying the improved version of the cascade model. It is shown that the collision-induced radiative quenching gives a significant contribution to the total disintegration of the $2 s$ state of muonic atoms at energies below the $2 s - 2 p$ threshold. The initial population of the $2 s$ state for both muonic hydrogen and deuterium atoms, absolute intensities and probabilities of the different disintegration modes as well as their lifetimes are calculated for the fractions with kinetic energies above and below the $2 s - 2 p$ threshold. The obtained results are compared with the known experimental data.
Comments:
11 pages, 14 figures
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
arXiv:
2112.15197 [pdf]
PRA(2022)·4 citations
09
[Submitted on 31 Dec 2021] (cross-list from hep-lat)
Critical behavior towards the chiral limit at vanishing and non-vanishing chemical potentials
Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Anirban Lahiri🇩🇪 · Sheng-Tai Li🇨🇳 · Mugdha Sarkar🇩🇪 · Christian Schmidt🇩🇪 · Philipp Scior🇺🇸
We study the scaling behavior of the (2+1)-flavor QCD crossover region towards the chiral limit with smaller-than-physical light quark mass gauge ensembles, generated using the HISQ fermion discretization. At zero chemical potential, we study the fluctuations of conserved charges and their correlations with the chiral condensate, towards the chiral limit. We analyse the role of universal and regular contributions to the above quantities. We find a preliminary estimate of the leading curvature coefficient of the chiral phase transition line using scaling arguments.
Comments:
11 pages, 7 figures; talk presented at The 38th International Symposium on Lattice Field Theory, LATTICE2021 26th-30th July, 2021, Zoom/Gather@Massachusetts Institute of Technology
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.15398 [pdf]
PoS(2022)·6 citations
10
[Submitted on 31 Dec 2021] (cross-list from hep-ph)
Hydrodynamic helicity polarization in relativistic heavy ion collisions
Cong Yi🇨🇳 · Shi Pu🇨🇳 · Jian-Hua Gao🇨🇳 · Di-Lun Yang🇹🇼
We study helicity polarization through the (3+1) dimensional relativistic viscous hydrodynamic models at $s_{N N} = 200$ GeV Au+Au collisions. Similar to the local spin polarization, we consider the helicity polarization beyond global equilibrium and investigate the contributions induced by thermal vorticity, shear viscous tensor, and the fluid acceleration. We find that the local helicity polarization induced by thermal vorticity dominates over other contributions. It also implies that in the low-energy collisions, the the fluid vorticity as part of thermal vorticity may play the crucial role to the total helicity polarization. Such a finding could be useful for probing the local strength of vorticity in rotational quark gluon plasmas by measuring helicity polarization. Our simulation confirms the strict space reversal symmetry, whereas we also compare our numerical results with approximated relations derived from ideal Bjorken flow. Our studies also provide a baseline for the future investigation on local parity violation through the correlations of helicity polarization.
Comments:
27 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.15531 [pdf]
PRC(2022)·35 citations
11
[Submitted on 31 Dec 2021] (cross-list from hep-ph)
Analytic solutions of relativistic dissipative spin hydrodynamics with radial expansion in Gubser flow
Dong-Lin Wang🇨🇳 · Xin-Qing Xie🇨🇳 · Shuo Fang🇨🇳 · Shi Pu🇨🇳
We have derived the analytic solutions of dissipative relativistic spin hydrodynamics with Gubser expansion. Following the standard strategy of deriving the solutions in a Gubser flow, we take the Weyl rescaling and obtain the energy-momentum and angular momentum conversation equations in the $d S_{3} \times R$ space-time. We then derive the analytic solutions of spin density, spin potential and other thermodynamic in $d S_{3} \times R$ space-time and transform them back into Minkowski space-time $R^{3, 1}$ . In the Minkowski space-time, the spin density and spin potential including the information of radial expansion decay as $\sim L^{- 2} τ^{- 1}$ and $\sim L^{- 2} τ^{- 1/3}$ in large $L$ limit, with $τ$ being proper time and $L$ being the characteristic length of the system, respectively. Moreover, we observe the non-vanishing spin corrections to the energy density and other dissipative terms in the Belinfante form of dissipative spin hydrodynamics. Our results can also be used as test beds for future simulations of relativistic dissipative spin hydrodynamics.
Comments:
28 pages; 1 table and 1 figure are added
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.15535 [pdf]
PRD(2022)·45 citations
12
[Submitted on 31 Dec 2021] (cross-list from hep-ph)
Meson structure on the light-front III : The Hamiltonian, heavy quarkonia, spin and orbit mixing
Edward Shuryak🇺🇸 · Ismail Zahed🇺🇸
This is the third paper on hadronic light front wave functions (LFWFs). We derive a light front Hamiltonian from first principles using the key features of the QCD vacuum at low resolution. In the first approximation, it gives transverse oscillator and longitudinal harmonic modes and yields the correct Regge trajectories. For heavy quarkonia, we compare its spectrum to that obtained from the usual Schroedinger equation in the rest frame. We use the same approach for light quarks, and investigate the role of confinement and chiral symmetry breaking in the quark-antiquark sector. We then study spin-spin and spin-orbit mixing, resulting in e.g. quadrupole moments of vector mesons. For the light mesons, we show how to extend the famed t $^{'}$ Hooft interaction to the light front, which solves the U(1) problem and helps produce a light pion. We use the ensuing light front wavefunctions, to derive the pertinent parton distribution functions, parton amplitudes and low energy constants.
Comments:
37 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2112.15586 [pdf]
PRD(2023)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE